Increasingly stringent pollution control standards for acid gases and trace air toxics, including hydrochloric acid (HCl), sulfur trioxide (SO3), and mercury (Hg), pose greater challenges for industries. Current best control practices for sorbent pollution control processes, such as activated carbon injection (ACI) and dry sorbent injection (DSI), must be improved. In many cases, a further increase in sorbent injection rate is uneconomical, ineffective, and/or otherwise adversely impacts the waste gas treatment process.
External constraints can also hamper additive or sorbent performance. The effectiveness of in-duct sorbent injection can often be limited due to constraints of duct layout, non-ideal injection locations, sorbent in-flight residence time, temperature, adverse flue gas chemistry, and close proximity to particulate control device.
Devices placed in the duct to improve additive or sorbent performance, such as in-line gas mixing devices, can cause operational issues. At periods of high load, for example when a power plant is running at or near full capacity during summer extremes, the pressure drop caused by can cause a measurable impact on plant performance and efficiency.
There is therefore a need for improved methods of sorbent/gas mixing that can be implemented in limited duct space while maintaining plant operational parameters within acceptable levels.
There is a further need for methods and systems that can achieve desired sorbent/gas mixing with lower pressure drop at high or peak load conditions.